''Cylindroteuthis'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

belemnite Belemnitida (or the belemnite) is an extinct order of squid-like cephalopods that existed from the Late Triassic to Late Cretaceous. Unlike squid, belemnites had an internal skeleton that made up the cone. The parts are, from the arms-most to ...

that lived from the

Early Jurassic The Early Jurassic Epoch (in chronostratigraphy corresponding to the Lower Jurassic Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic-Jurassic extinction event, 201.3 Ma ...

to the

Early Cretaceous The Early Cretaceous (geochronological name) or the Lower Cretaceous ( chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145 Ma to 100.5 Ma. Geology Pr ...

. Its fossils have been found in Asia, Europe, North America, and New Zealand.

Taxonomical history

''Cylindroteuthis'' was first described in 1879 by Claude-Emile Bayle. A belemnite originally described as the ''Cylindroteuthis'' species ''C. confessa'' has been re-described as '' Mesoteuthis soloniensis''.

Biology and fossil finds

''Cylindroteuthis'' is a common find from several Jurassic formations. Specimen length ranges from . The most commonly preserved part of the animal is its guard, or rostrum, which was composed of

calcite Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on the Mohs scale of mineral hardness, based on scra ...

. The guard would not have been found on the exterior of ''Cylindroteuthis'', as traces of

blood vessel Blood vessels are the structures of the circulatory system that transport blood throughout the human body. These vessels transport blood cells, nutrients, and oxygen to the tissues of the body. They also take waste and carbon dioxide away from ...

s have been discovered on some guards, suggesting that it was an internal feature. The guard housed a phragmocone, which allowed ''Cylindroteuthis'' to maintain

buoyancy Buoyancy (), or upthrust, is an upward force exerted by a fluid that opposes the weight of a partially or fully immersed object. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus the p ...

in water. Some better-preserved specimens have features similar to modern

squid True squid are molluscs with an elongated soft body, large eyes, eight arms, and two tentacles in the superorder Decapodiformes, though many other molluscs within the broader Neocoleoidea are also called squid despite not strictly fitting ...

, such as ten arm-like appendages and an

ink sac An ink sac is an anatomical feature that is found in many cephalopod mollusks used to produce the defensive cephalopod ink. With the exception of nocturnal and very deep water cephalopods, all Coleoidea (squid, octopus and cuttlefish) which dwell ...

, intact. ''Cylindroteuthis'' has been recovered from the Temaikan Boatlanding Bay formation of

Australasia Australasia is a region that comprises Australia, New Zealand and some neighbouring islands in the Pacific Ocean. The term is used in a number of different contexts, including geopolitically, physiogeographically, philologically, and ecolo ...

. Three species of ''Cylindroteuthis'' (''C. knoxvillensis'', ''C. cf. newvillensis'', and ''C. venusta'') have been described from the

Arctic The Arctic ( or ) is a polar region located at the northernmost part of Earth. The Arctic consists of the Arctic Ocean, adjacent seas, and parts of Canada ( Yukon, Northwest Territories, Nunavut), Danish Realm ( Greenland), Finland, Iceland ...

region. In addition, about 2350 belemnite guards (including those of ''Cylindroteuthis'') have been recovered from Lower Cretaceous formations of northeastern

Greenland Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland is ...

, suggesting the presence of a sort of "immigration route" for belemnites. The findings also suggest the existence of a "proto Gulf-stream" as early as the

Valanginian In the geologic timescale, the Valanginian is an age or stage of the Early or Lower Cretaceous. It spans between 139.8 ± 3.0 Ma and 132.9 ± 2.0 Ma (million years ago). The Valanginian Stage succeeds the Berriasian Stage of the Lower Cretac ...

. Another species, ''C. cf. obeliscoides'' is associated with the early Cretaceous One Tree Formation of

Vancouver Island Vancouver Island is an island in the northeastern Pacific Ocean and part of the Canadian province of British Columbia. The island is in length, in width at its widest point, and in total area, while are of land. The island is the largest by ...

.Ludvigsen, Rolf & Beard, Graham. 1997. West Coast Fossils: A Guide to the Ancient Life of Vancouver Island. pg. 93-94

References

* ''Fossils'' (Smithsonian Handbooks) by David Ward (Page 163)

External links

''Cylindroteuthis''
in the

Paleobiology Database The Paleobiology Database is an online resource for information on the distribution and classification of fossil animals, plants, and microorganisms. History The Paleobiology Database (PBDB) originated in the NCEAS-funded Phanerozoic Marine Paleo ...

{{Taxonbar, from=Q4119243 Belemnites Jurassic cephalopods Cretaceous cephalopods Prehistoric cephalopod genera Mesozoic cephalopods of Asia Mesozoic cephalopods of North America Cretaceous cephalopods of Europe Mesozoic cephalopods of Europe Early Jurassic genus first appearances Early Cretaceous genus extinctions